H bridge drivers include two high side transistors and two low side transistors, and are configured such that each high side transistor is in series with a respective low side transistor and a load is coupled to the nodes between the pairs of high side and low side transistors. Each pair of high side and low side transistors is called a half-bridge. A gate driver circuit converts a control signal to a power signal that can efficiently turn on and off each transistor in the H bridge driver. To prevent shoot-through conditions within a half-bridge during transitions from high to low or low to high, dead time is inserted between turning off of one transistor and turning on of the other. The length of the dead time is often equal to the time required to turn on or turn off a transistor in the half-bridge driver. However, dead time limits the operating frequency of the H bridge driver and allows power dissipation through transistors in the H bridge driver.
Some gate driver circuits reduce power dissipation during dead time by turning the transistor on and off more quickly. This may increase the efficiency of the H bridge driver, but at the cost of creating electromagnetic interference (EMI) in the integrated circuit (IC), disrupting operation of other circuits in the IC. Some gate driver circuits balance the need for quick turn on and turn off times with controlled EMI by implementing comparators to detect different regions of operation for each transistor during turn on and turn off, and quickening only the regions that are unlikely to cause EMI. However, these comparators must be tuned for each transistor, system voltage, motor type, board parasitics, and the like, and often experience degrading performance over time as system parameters change, for example as temperature or the supply voltage changes.